Skip to main content

Full text of "The ocean sunfish (Family Molidae)."

\jP Biodiversity 
fe^HeriUge 

http://www.biodiversitylibrary.org 



Bulletin of the British Museum (Natural History). 

London :BM(NH) 
http://www.biodiversitylibrary.org/bibliography/2202 



1 : http://www.biodiversitylibrary.org/item/19429 

Page(s): Page 87, Page 88, Page 89, Page 90, Page 91 , Page 92, Page 93, Page 94, Page 95, 

Page 96, Page 97, Page 98, Page 99, Page 100, Page 101, Page 102, Page 103, Page 104, 

Page 1 05, Page 1 06, Page 1 07, Page 1 08, Page 1 09, Page 1 1 0, Page 111, Page 1 1 2, Page 

1 1 3, Page 1 1 4, Page 1 1 5, Page 1 1 6, Page 1 1 7, Page 1 1 8, Page 1 1 9, Page 1 20, Page 1 21 , 

Page 1 22, Text, Text 



Contributed by: Natural History Museum, London 
Sponsored by: Natural History Museum Library, London 



Generated 30 August 2010 8:05 AM 
http://www.biodiversitylibrary.org/pdf3/004068300019429 



This page intentionally left blank. 



THE OCEAN SUNFISHES 
(FAMILY MOLIDAE) 



BY 



A. FRASER-BRUNNER 




X 





Pp. 87-121; t8 Text-figures 



BULLETIN OF 



THE BRITISH MUSEUM (NATURAL HISTORY) 

ZOOLOGY Vol. I No. 6 

LONDON : 1951 




THE BULLETIN OF THE BRITISH MUSEUM 
(NATURAL HISTORY), instituted in 1949, is to be 
issued in five series, corresponding to the Departments 
of the Museum. 

Parts will appear at irregular intervals as they 
become ready. Volumes will contain about three or four 
hundred pages, and will not necessarily be completed 
within one calendar year. 

This paper is VoL J, No. 6 of the Zoology series. 



PRINTED BY ORDER OF THE TRUSTEES OF 

THE BRITISH MUSEUM 



Issued November igSi Price Seven Shillings and Sixpence 




THE OCEAN SUNFISHES (FAMILY MOLIDAE) 

By A. FRASER-BRUNNER 

SYNOPSIS 

The relationships of the Molidae with other Plectognathi are briefly discussed. The movable lobe at the 
hind margin of the body, supported usually by migrant dorsal and anal rays but sometimes also by 
caudal rays centrally, is designated the ' clavus\ Three genera are recognized, assigned to two subfamilies. 
Masturus is shown to include two forms (treated as species but possibly the sexes of one) . Evidence is 
presented to show that in this genus alone of the family some caudal rays are developed. Mola is shown 
to include two species, which are diagnosed and figured. Sexual dimorphism in Mola mola is described. 
Full synonymies are included, 

ON account of their curious form and the great size which they often attain, the fishes 
of the family Molidae, usually called Ocean Sunfishes, have attracted considerable 
attention from early times, A large and scattered literature exists concerning them, 
but although comparative studies have been made from time to time and their 
anatomy has received attention quite frequently, we are stiU far from a complete 
understanding of their relationships. This is mainly because all the species are rather 
rare, and their occurrence unpredictable, so that it is not possible to make an excur- 
sion for the express purpose of collecting specimens, as could be done with many other 
fishes, while the great size of most examples makes transportation and preservation 
a difficult problem. Consequently good comparative material is not easily available 
for study, and much reliance has to be placed upon published descriptions and figures. 

It is the purpose of the present work to draw attention to certain facts which have 
become apparent from a study of the literature, aided by the material in the national 
collection. 

My thanks are due to Mr. G. Palmer for his assistance in seeking out some of the 
references and checking a number of points in them. 

I am concerned here only with taxonomy within the family, since a full considera- 
tion of their relationship to other Plectognathous fishes will be included in a larger 
work upon the anatomy and phylogeny of the whole Order now in preparation. It 
can be pointed out here, however, that I have already indicated in an earUer paper 
(Fraser-Brunner, 1943), that the Molidae are not really as highly specialized as 
previously supposed. Their main peculiarity lies in the atrophy of the rear end of the 
vertebral column, resulting in a mechanical rearrangement of the median fin- 
structures closely resembling that seen in other fishes when the tail is amputated a. 
an early age ; some interesting examples of this among Flatfishes have been given by 
Chabanaud (1935)- The resemblance is not quite perfect, since with amputation the 
supporting bones of dorsal and anal fins are lost with the tail, whereas in the Mohdae 
only the vertebral structures are lost. 

The lateralis muscles of the trunk, deprived of their normal attachment, become 
inserted upon the deep muscles of the dorsal and anal fins, and progressively lose 
their identity in the genera Ranzania, Masturus, Mola. The result of this is that body- 
flexion is lost but the dorsal and anal fins gain in power, and the latter are therefore 



go THE OCEAN SUNFISHES (FAMILY MOLIDAE} 

the principal means of locomotion. The posterior parts of these two fins extend round 
the rear end of the truncated body to support a broad, stiff lobe which acts as a 
rudder. This has been called the 'pseudo-caudal' by Raven {1939 a), but this is not 
a very suitable term in my opinion ; any structure in this part of the body may be 
described as 'caudar, and even if 'pseudo-caudal fin' is used, this is not true for all 
the species, for I hope to demonstrate on a later page that remains of the true caudal 
fin are included in the structure in Masiurus, 

For this rudder-like lobe at the end of the body in the Molidae I therefore propose 
using a new term, and throughout this paper it will be called ' the clavus ' (Lat, clavus, 
a rudder) . 

Apart from these changes of form, all of which are demanded as mechanical 
consequences of the phyletic atrophy of the posterior part of the vertebral column, 
the Sunfishes resemble in their anatomy the more primitive of the Tetraodont fishes, 
and in one feature at least, the retention of the fourth gill, they are less modified even 
than those. They stand, therefore, near the main stem of the Tetraodont s, and 
attempts to derive them from the highly modified Diodontidae seem to me to be very 
far-fetched ; whatever resemblances the latter may show are more plausibly explained 
by the assumption that they are evolved from a Mola-hke type (before caudal 
atrophy) rather than the reverse. The MoHdae show also some features in common 
with the Ostraciontoidea alone among Plectognathi, and indicate therefore the diver- 
gence of the Trunkfishes and Puffer-fishes from a common stock during their evolu- 
tion. 

In my classification of the Tetraodontoidea I expressed the view that only two 
genera of Mohdae should be recognized. This w^as based on the belief, current at that 
time, that Ranzania, Masiurus, and Mola were each represented by a single species, 
and since the latter two forms seemed to be more closely related to each other than 
to Ranzania, it appeared that this relationship would be better expressed by placing 
them together in the genus Mola. A more detailed examination of these fishes, 
however, has caused me to modify these views* 

Firstly, I find that there are two species of Mola in the limited sense — one of world- 
wide distribution and the other apparently restricted to the Australasian region. 
Whitley (193 1) recently revived the name Mola ramsayi Giglioli 1883 for the latter, 
but was apparently unaware of its distinguishing characters and assumed that all 
specimens from that region should be so named, whereas his main description appears 
to be of M, mola and the records show that both M. mola and M. ramsayi are to be 
found around Australasia. The type of M. ramsayi, a huge stuffed specimen, is in the 
British Museum (Natural History) , and by a piece of good fortune one of our spirit- 
specimens belongs to that species, so that I have been able to make direct comparison 
with examples of M, mola of similar size. 

Secondly, a close study of the literature concerning Masiurus lanceolalus, aided 
considerably by the excellent work of Gudger on this subject, reveals that two forms 
are included here also, though it is not certain that they are different species. More 
interesting is the apparent fact that in Masiurus alone of the family a remnant of the 
caudal fin is included in the support of the clavus. In this and in its musculature it is 
a little less specialized than Mola, and it therefore now seems desirable to recognize 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



gi 



it as a distinct genus in order to express its relationship to the other genera more 

clearly. 

There has been much speculation in the past as to whether the rays supporting the 
clavus belong to the caudal fin or to the dorsal and anal, and even Gregory & Raven 
(1934), when describing the anatomy of M. mola, thought them to be caudal although 
their description and figure indicate that they are not (an error corrected by Raven 
in 1939)- Apart from internal anatomy, the number of these rays is in most cases 
against the likelihood that they all belong to the caudal fin ; in most Plectognathi 




Fig, I, Diagram illustrating reduction of the caudal region in the Molidae. 

Persistent parts of the axial skeleton shown in black ; atrophied parts shown with broken 

Une; the last intemenral and interhaemal bones close in along the lines marked with 

arrows. {Based on Ryder, 1886, modified by reference to adult and larval forms*) 

there are only 12 caudal rays, exceptionally 13, and sometimes as few as 10, But in 
Ranzania and Masturus the clavus is supported by 20 or more rays, in Mola ramsayi 
by 16, and only in Mola mola by 12. 

These rays are, in the main, supported by elements which have all the appearance 
of belonging to the series of inter spinous supports of the dorsal and anal fins, but have 
been rotated to lie roughly at right angles to the last normal vertebro-interspinous 
complex by the process which has already been suggested by Ryder (Fig. i). The 
skeletal supports of the clavus are accompanied by muscles which have split off from 
the inclinators of the dorsal and anal fins, and caudal muscles appear to have been 
lost with the posterior vertebral structures. Reduction of the caudal region can be 
shown to extend to the number of rays supporting the clavus. Thus in Ranzania, 
which has x8 remaining vertebrae, there are 22 rays of dorsal and anal origin in the 
clavus ; in Mastunis and Mola, which have 17 vertebrae, we find the series; Masturtis 
14-18 (exclusive of caudal rays), Mola ramsayi 16, M, mola 12, 

Alongside this the form of the rays is of interest (see Barnard, 1935). In Ranzania 



92 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



^Mo^ 



'fyiaituiui 



each ray in the clavus (except the outermost) is abruptly branched at its distal end 
(like those of the dorsal and anal lobes) and forms a fairly stiff fan-shaped support, 
closely apposed to those each side of it. In Mola this branched portion becomes 
hyperossified into a single plate or ossicle characteristic of the genus, the number and 
arrangement of these ossicles being of importance in specific diagnosis. 

In Mastums the rays seem never to be branched in adults, and are never ossified 
distally, but in young examples they may be branched at the tip hke those of Ran- 
zania. This development can be seen by comparing the figures accompanying this 
paper. Between the rays in Ranzania lie elongate lobes of apparently collagenous 
material (shown in Fig. 3)^ and it is probably these which in Mola mola extend back 

between the widely spaced rays to form the 
lobes characteristic of the clavus of large speci- 
mens of that species- 

As a matter of interest, it may be remarked 
that Ranzania, Mola, and the Percomorphous 
family Carapidae (Fierasferidae) are the only 
fishes to which the term ' gephyrocercal ' can 
properly be applied, as pointed out by Ryder 
when originally proposing the term. 

Raven has taken the view that Ranzania is 
the most specialized of these genera. I cannot 
agree with this. Its skeleton is much less de- 
generate than that of Mola^ more strongly ossi- 
fied, and there are 18 or ig vertebrae. The 
lateralis muscles are stiU moderately developed, 
though inserted posteriorly on the w. dorsalis 
profundus ; the usual division of the dorsal por- 
tion into superior and inferior parts is still quite 
distinct anteriorly. I feel sure that Raven was 
mistaken in identif5dng the lateralis muscles as 
dorsal and anal depressors ; they insert on to the 
latter but are distinct. The gill-rakers are free 
and apparently functional as in more generalized fishes. Further, this species is not 
gigantic. 

It is not suggested, however, that Ranzania is completely representative of the 
ancestor of the other two genera ; it has retained more primitive features, but it has 
completely lost the caudal fin, whereas Masturus, w^hich is otherwise a stage farther 
towards Mola, retains a vestige of this fin, as will be shown later. 

The relationships of these genera are therefore probably as shown in Fig. 2. An 
ancestral form in which the skeleton and musculature is still fairly normal and the 
caudal fin not completely lost gives rise to Ranzania on the one hand, which loses its 
caudal fin, and to Masturus on the other, in which the caudal fin retains a precarious 
hold but the skeleton and the musculature deteriorate. Further degeneration and 
complete loss of the caudal fin in this second line gives us Mola. 

Tlie need to recognize Mastttrus and Mola as more closely related to each other 





Fig. 2, Relationships of the genera of 
the family Molidae. 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



93 



than to Ranzania therefore still remains, and these two lines can now be expressed as 

subfamilies. 

The three genera illustrate quite well the manner in which the lateralis muscles lose 
their primary function of flexing the body and become successively more closely 
associated with the dorsal and anal fins, their added power enabling these fins to 




Fig. 3, Ranzania laevis, adult. A specimen 515 mm. long, from Baltimore, 

County Cork, Ireland. 

become proportionately larger. The body is therefore held rigid, assisted in 
Ranzania by a carapace similar to that of Strophiurichthys among the Ostracionts, 
but with much smaller hexagonal plates; in Alasturtis and Mola this carapace is 
reduced to small denticles, and rigidity is assisted by a thick collagenous layer 
beneath the skin (Green, 1901). 

All the species pass through a remarkable metamorphosis. The newly hatched 
larvae are Teiraodon-like, but soon {at 1-8 mm.) develop a cuirass of broad plates 
with jutting triangular projections, looking more reminiscent of an Ostraciont 
(Richardson named this stage Ostracion hoops). With the atrophy of the larval tail, 
Ranzania seems to pass, by reduction of the cuirass and elongation of the body, into 



94 THE OCEAN SUNFISHES (FAMILY MOLIDAE) 

a form essentially like that of the adult though proportionately longer, but Masturus 
and Mola show an intermediate stage, wherein the cuirass breaks up into small 
denticles and the triangular projections grow into long sharp spines on broad poly- 
gonal grooved bases (very like those of Acanihostracion or Lactoria), This stage is 
much shorter in the body than the adult. As growth proceeds the body lengthens and 
the spines shorten and disappear, though in Mola the bases of one on the snout and 
one at the chin are nearly always retained even in the largest specimens, 

KEY TO THE GENERA OF MOLIDAE 

I. Form comparatively elongate. Vertebrae 8-[-io or ii. Carapace of smooth hexa- 
gonal plates,' terminating at bases of dorsal and anal fins and clavus. Lips pro- 
duced forward beyond teeth as a funnel, closing as a vertical slit. Gill-rakers free. 
2 Uppermost branchiostegal rays coalesced. Clavus with 22 rays, all borne 
on interspinous bones. No secondary post-larval metamorphosis (subfamily 
Ranzaniinae) . . ♦ . . . , , .1, Ranzania 

II* Form shorter. Vertebrae 9+8, Carapace collagenous; skin of body and clavus 
with small rough denticles. Lips not funnel-hke, Gill-rakers concealed in thick 
skin. 6 distinct branchiostegal rays. A secondary post-larval metamorphosis 
(subfamily Molinae). 

A. Median rays of clavus not borne on interspinous bones, supporting 
a pronounced lobe; none of the rays bearing ossifications 

distally • • * . . . . , , 3. Masturus 

B. All rays in clavus borne on interspinous bones, most of them terminating 
in an ossification distally •••*•, 3. Mola 

Genus RANZANIA Nardo 

? Triurus Lacepfede, 1800, Hist NaL Poiss, 2: 200. Type: Triurus bougainvilUanus Lacepede* 
Ranzania Nardo, 1840, Ann. Sci. Regno Lombardo-Veneio, 5: 10, 105. Type: Ranzania typus 

Nardo (= Ostracion laevis Pennant}. 
Centaurus Kaup, 1855, Arch. Nafurgesch, 21 (i): 221, Type: Ostracion hoops Richardson (= Os- 

tracion laevis Pennant, young). 

The characters of this genus have been indicated concisely in the foregoing key. 

Lacepede's description of Triurus bougainvilUanus was based upon manuscript 
notes by Commerson. It could be interpreted as referring to the fish later known as 
Ranzania, but to describe the funnel-like lips as 'rictu fistulari' or 'le museau avance 
en forme de tube ' and again ' un museau tres prolonge fait en forme de tube assez 
etroit' requires a good stretch of imagination. Moreover, the depth of the body is 
given as the proportion of 18 against the body-length of 71, and no other Sunfish has 
been recorded as slender as that. Finally, it has to be noted that in voL i of the same 
work Ranzania is figured {pi 22) under the name 'le Tetrodon lune\ The status of 
the name Triurus is therefore doubtful, and I hesitate to follow \'l'Tiitley in using it, 
particularly since the name Ranzania is so well known. 

A single species- 

^ In young specimens (go mm.) each plate has a prominent bony tubercle centrally. 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 95 

Ranzania laevis (Pennant) 

Ostracion laevis Pennant, 1776, Brit. Zool, ed. 4, 3: 129. pl* ^9- 

Tetrodon truncatus Retzius, 1785, if . Svenska Vetensk Akad. HandL 6 (2) : 121 {based on Pennant) ; 
Lacepede, 1798, Hist. NaL Poiss. 1: 514, pL 22 f. 2; Donovan, 1808, Nat. Hist. Brit. Fish. 

2: pL 41. 

Orthragoriscus oblongus Bloch & Schneider, 1801, Syst. Ichth.: 511, pL xcviii. 

Orthagoriscus oblongus Jenyns, 1835, Man. Brit. Vertebr. Amm.i 491; Yarrell, 1836, Hist. Brit, 
Fish, 2: 357, fig.; Conch, 1841, Ann. Mag. Nat. Hist. 6: 144; Bonaparte, 1846, Cat. Met. 
Pesci eur.: 88; Bleeker, i860, Natunrk. Tijdschr, Ned.-Ind. 21; 57; Couch, 1865, Hist, Fish, 
Brit. 7s, 4: 381, pi, 246 ; Harting, 1868, Verh. Akad. Wet. Amst. : 12, pL 2, fig, 2 ; Andrews, 1871, 
Proc. Nat. Hist. Sac, Dublifi, 5; 123; Sauvage, 1891, Hist. Madagascar, 16 (Poiss.) : 529; 
Nobre, 1935, Faun. Mar. Portugal, Vertebr.: 242. 

Cephalus oblongus Shaw, 1806, Gen. Zool. 5: 439. pl- ^^7^; Swainson, 1839, Nat. Hist. Class, Fish, 

2: 33O' 

Cephalus varius Shaw, 1806, ibid. 

Orthragus commersoni Rafinesque, 18 10, Caratt, Sioilia: 18- 

Orthragus oblongus Rafinesque, i8io, Indies Itt, SiciL: 40. 

Tetraodon truncatus Couch, 1825, Trans. Linn. Sac. Land. 14: 88, 

Cephalus elongatus Risso, 1826, Eur. Merid. 3; 173* 

Mala planci Nardo, 1828, BulL Sci. Nat. Fdrussac, 13: 437. 

Orthagoriscus truncatus Fleming, 1828, Hist. Brit. Anim.: 175; Giinther, 1870, Cat. Fish. Brit. 
Mus. 8: 319; Bleeker, 1873, Ned. Tijdschr. Dierk, 4: 121 ; 1879, Verh. Akad. Wed. Amst. 18: 26; 
Rochebrune, 1883-1885, Faune SinSgambie (Poiss,): 157; Day, 1884, Fish. Gt. Brit.: 276, 
pL 149; Beauregard, 1893, BulL Sac. Sci. Nat. Quest, 3: 229 ; Scharfif, 1906, Irish NaL 15: 275 ; 
Mauro, 1906, BolL Accad. Gioenia, Catania, n.s. 85: i6j fig. 

Cephalus cocherani Traill, 1832, Mem, Werner: 6. 

Orthragoriscus elegans Ranzani, 1839, Novi Comment. Acad. Sci. Inst. Bonon, 3; table. 

Orthragoriscus hattarae Ranzani, 1839, ibid. 

Ranzania typus Nardo, 1840, Ann. Sci, Regno Lombardo-Veneto, 5: 105; Smith, 1949, Sea Fish. 
S, Afr.: 422, pL 95, fig, 1212. 

Ostracion boops Richardson, 1844, Voy. Erebus and Terror, Fish. : 52, pl. 30, figs, 18-21 ; Giinther, 
1880, Intro, Study Fish.: 175, fig, 93. 

Orthagoriscus planci Bonaparte, 1846, Cat. Met. pesci eur.: 88; Caciestrini^ 1872, Fauna dFtalia, 
Pesci: 149; Stossich, 1879, Boll. Soc. Adriat. Sci. Nat, 5: 36, 

Orthragoriscus lunaris (Gronow) Gray, 1854, Cat, Fish.: 165, 

Centaurus boops Kaup, 1855, Arch. Naturgesch, 21 (i): 221, 

Ranzania truncata Jordan & Gilbert, 1883, Bull. U.S. Nat, Mus, 16: 966; Trois, 1884, Atti IsL 
Veneto, 2 (6) pt. i: 1269, pis. 12-14; pt- 2: 1543, pl. 16; Perugia, 1897, Ann. Mus. Stor, nat. 
Genova (2), 18: 140; Jordan & Evermann, 1898, BulL U.S. Nat. Mus. : 47 (2) : 1755 ; Steenstrup 
& Liitken, 1898, K. danske vidensk. Selsk, Skr. (6) 9; 54, fig. ; Giinther, 19 10, /. Mus. Godeffroy, 
% (17) : 477; Pellegrin, 1912, BulL Soc, Zool. France, 37: 228, fig, i ; Ribeiro, 1915, Arch. Mus. 
nac. Rio de J. 17 {Mohdae) : 4, pl. ; Thompson, 1918, Mar. BioL Rep. Cape Town 4: 176; Buen, 
1919, Bol, Pesc. Madr. 4: 295; 1935, Notas Inst. esp. Oceanogr. 2 (81): 146; Schmidt, 1921, 
Nature, Land, 107: 76, figs* 2, 4, 5; Medd, Komm. HavundersBg. Fisk. 6 (6), fig. 2. 13, pL i, 
fig* 7 ; Fowler, 1922, Copeia 112; 84 ; Vinciguerra, 1923, Comune di Genova 3: 5, fig. 3 ; Barnard, 
1927, Ann. S. Afr. Mus. 21: 989, fig. 32; Fowler, 1928, Mem. Bishop Mus. 10: 475 ; Schmidt, 
1932, Dana's Togt omkr. Jord.: 251, fig* 197 {6-11} ; Gudger, 1935, Nature, Lond. 135: 548; 
Barnard, 1935, Ann, S, Afr. Mus, 30: 655, fig. 6c:; Ehrenbaum, 1936, Handb. Seefisch. Nord- 
europ. 2: 88, fig, 6g; Gudger, 1936, Nature, Lond. 137; 947; Fowler, 1936, BulL Amer. Mus. 
Nat, Hist. 70 (2}: 1123, fig. 470; Ninni, 1939, Atti. Soc. Ital. Sci. naL 78: 236; Raven, 1939, 
Amer. Mus. Novit. 1038» figs. 1-3; Clark, 1949, ibid. 1397: 7 3 fig. 9; Maul^ 1949* Vertebr, 
Madeira 2 (Peixes) ; 158. 

Ranzania makua Jenkins, 1895, Proc. Calif. Acad. Sci. {2) 5: 780, pl.; Fowler, 1900, Proc* Acad. 

ZOOL. I. 6 H 



g6 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



Nat. Sci. Pkilad.: 514; Jordan & Snyder, 1901, Proc. U.S. Nat. Mus. 24: 262 ; Jenkins, 1902, 

BulL U.S. Fish. Comm. 22: 486 (1903); Jordan & Evermann, 1905, Bull. US, Fish, Comm. 

23 {i): 439, fig- 194; Jordan, Tanaka, & Snyder, I9i3> /. CoJL Sci. Tokyo 33: 231, fig. 166; 

Snyder, 1913, Proc. U.S. Nat Mus. 44: 460, pL 63; Tanaka, 1914, Fig. Descr. Fish. Japan 

16; 274, pL 76; Jordan & Jordan, 1922, Mem, Carneg. Mus. 10 (i): 89; Jordan, Evermann, & 

Tanaka, 1927, Proc. Calif, Acad, Sci. 16 {4): 680, 
Orthagoriscus (larva) Sanzo, 191 9, Mem. R. Com. Talassogr. itaL 69: 1-7, figs. 1-4. 
Ranzania laevis Whitley, 1933, Vict. Nat. 49: 211, figs, 6, 7 ; Phillips, 1941, Trans. Proc. Roy. Soc, 

N.Z. 71 (3) : 245, pL 41, fig. 6; Deraniyagala, 1944, /- Bombay Nat, Hist. Soc. 44 (3) : 429. 
Triurus /aet/is Whitley, 1937, -^^^- Queensland Mus. 11 (2): 147; Hale, 1944. S. Aust, Nat, 22: 

pt, 4, pL I, figs. 





Fig. 4, Ranzania laevis. Front view of head, showing mouth open and closed. 

Examination of the records leaves little doubt that a single species of Ranzania 
ranges the seas of the whole world except the polar regions, but it seems that two 
subspecies can be recognized as follows : 

Ranzania laevis laevis (Pennant), Depth of carapace contained twice or more in 
its length, in adults {up to 580 mm.)- Axil of pectoral fin weU below level of 
centre of eye. Height of anal fin less than | length of head, Atlantic Ocean. 

R. I, makua Jenkins, Depth of carapace contained less than twice in its length, 
in adults (400-500 mm.). Axil of pectoral iin above level of centre of eye. 
Height of anal fin | length of head or more. North Pacific Ocean. 

That these two forms are simply subspecific extremes in the range is shown by the 
records from the Indian Ocean, wherein the depth is usually given as for makua while 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



97 



the pectoral fin is low as in laevis. A specimen from Mauritius in our collection shows 
these features well, and a closely similar specimen has been figured by Whitley from 

Australia. 

Whenever the coloration has been described it has been shown to be closely similar 
in all these forms, a pattern of pale transverse bands on a darker ground, the bands 
edged with spots and broken lines of black ; three bands associated with the eye are 




Fig. 5. Development of Ranzania laevis, 

A, larva (i-? mm.) ; B, C, D, early, full, and late 'Osttacion boops* stage; E^ transition to adult form 

(8 mm,)* (After Schmidt.) 



the most constant, the posterior ones being variously broken or anastomosed, some- 
times enclosing large oval areas of the ground colour. The colours are said to be very 
brilliant in life. 

The mouth is very curious, the lips extending well beyond the teeth and forming a 
funnel, the mouth being oval with the long axis vertical. The orifice closes along this 
axis, so that the rictus is really vertical — apparently unique among fishes (Fig. 4), 
This feature was shown clearly in the earhest published picture of the fish (Aldro- 
vandi, 1613), a remarkably good representation for its period. 

Too little is known of the feeding habits to show whether they can be associated 
with the peculiar mouth, but the species has been reported to take littoral algae 



98 THE OCEAN SUNFISHES (FAMILY MOLIDAE) 

(Barnard, 1927), and it is possible that the Hps can suck in and close upon a frond 
while the teeth nip it off. 

The fine developmental series given by Schmidt (1932) shows that Raven was 
correct in supposing that elongation of the body is secondary, but it also shows 
that Ranzania is never so greatly shortened as the other two genera {Fig. 5). 
Lengthening occurs after the 8-mm, stage, until at 53 mm. the length of the carapace 
is about 3 times its depth. This proportion is maintained up to 90'mm. size, and after 
that the depth of the body increases with growth, so that at 250 mm. the length of 
the carapace is 2*5 times its depth, at 430 mm. 2 25 times, at 515 mm. 2-i times, 
and at 580 mm, only twice. These figures are for the Atlantic form as shown by our 
specimens; in the North Pacific subspecies R, makua either the early lengthening is 
not so great or the later deepening is more rapid* 

The general use of the name truncatiis for this species seems to date from Glint her, 
1870; it is not clear why he chose this name rather than that of Pennant, on whose 
work that of Retzius was based, but possibly it was due to the fact that Pennant *s 
description was numbered 54, while on his plate the number 54 appears beside a 
figure of the ' Short Diodon ' [Mala mola), leaving the other Sunfish without a number. 
As both description and figure are titled ' Oblong Diodon ', however, this is clearly 
an error in numbering, and there can be no doubt as to the identity of Ostracion 
laevis, which antedates Tef radon Iruncatus by nine years. 

Ranzania laevis does not reach so enormous a size as the other members of the 
family, apparently not exceeding 800 mm. in length. It has been recorded from all 
warm seas, as far north as Scandinavia and far south as New Zealand, usually from 
single specimens — though it was once observed in great numbers at the surface of 
the water off Martinique (Pellegrin, 1912). As Schmidt has pointed out, most records 
of larval Sunfishes to date belong to this species, and he has given us a fairly complete 
picture of its development from egg to adult. 

Genus MASTURUS Gill 

Masiurus Gill, 1884, Proc, US. Nat. Mus. 7: 425. Type: Orihagoriscus oxyuropterus Bleeker. 

The study of this genus has been greatly facilitated by the careful bibhographical 
work of Gudger, who studied the records over a number of years, added several new 
ones, and finally in 1937 published a work dealing with the structure of the caudal 
region and another summarizing the knowledge of the genus up to that date. The 
latter two works are of great value, and the remarks which I make in the pages which 
follow are based largely upon them and should be considered with constant reference 
to them. 

The distinctness of Masturus from Mala had already been acknowledged by Steen- 
strup & Liitken (1898) , and discrimination between the post-larval forms was achieved 
by Schmidt (1921), The secondary post-larval stage of Masturus is characterized by 
enormous elongation of the 'cornicles' (Fig. 6). But it remained for Gudger to dis- 
entangle the confusion in the literature, and it is no doubt because these necessitated 
a chronological arrangement of his data that he was unable to recognize the two 
forms involved. But an analvsis of the records leaves httle room for doubt that there 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



99 



are indeed two forms, one the generally accepted M, lanceolatus (Lienard), the other 
apparently taking M. oxyuropierus (Bleeker) as the earliest name. These will be 
diagnosed on a later page, but it is necessary to note their existence at this point in 
order to clarify the discussion which follows. I must stress now, however, that they 
are regarded here as species only because we have no knowledge to the contrary, 
but I suspect that they may prove to be the sexes of one species. Not one of the 




Fig, 6, Post-larvae of Masturus. 

Aj 'Os^racton boops' stage (2-8 mm.); B, * Molacantkus^ stage 

(5 mm.)* (After Schmidt*) 

Specimens so far recorded has been sexed* Raven, the only person to make a dissec- 
tion, does not even mention the gonads. 

Masturus is peculiar among the Molidae in the possession of a pronounced lobe a 
little above the centre of the clavus* Gudger continually stressed the dorsal situation 
of this lobe, apparently as evidence that it could not be the remains of the larval tail ; 
this is not a very good point, for his own anatomical figures show that the lobe is 
associated with the end of the vertebral column. In other Plectognathi the vertebral 
column lies dorsally until it enters the caudal peduncle, where it lies approximately 
in the central long axis of the body. The fact that in the Molidae the vertebral column 
is dorsally placed at its hind end is therefore interesting as a further demonstration 
that the posterior part of the column is lost. 

It is my belief that the lobe on the clavus of Masturus can truly be called the 



lOO 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



'caudal lobe\ for all the illustrations of its anatomy so far given seem to demonstrate 
that the slender rays supporting it are caudal rays. The first to be published was that 
by Ryder, after a drawing by Putnam ; it was reproduced by Gudger, and is now 
copied as my Fig, 7 A, It is interesting in that the dorsal and anal rays of the clavus 
are shown branched, a feature shown only once elsewhere in the Uterature (Gudger, 
1939), perhaps because the tips are so often broken off in young specimens. They are 





JNH9 



B 



Fig, 7. Caudal skeletons of A, Masturus oxyuropterus, copied from Ryder, 1886; B, Masturus 

lanceolatus, copied from Gudger, 1937. 
c, caudal rays; ikn, intemeural bones; inh, interhaemal bones. 

thus distinguishable at a glance from the simple caudal rays in the middle, but it is 
probable that the outermost two of the latter are also of dorsal and anal origin, for 
they have each a small skeletal support. 

The interspinous bones supporting the clavus are shown completely fused with the 
hindmost remaining haemal spine. Comparison with other dissections shows that 
these must in fact have been distinct elements. The shape of the supporting bones of 
the dorsal and anal fin lobes is obscured by the inclinator muscles in this figure, but 
the drawing of these muscles is interesting in helping to show their character after the 
lateralis mass has been removed. 

Each of the rays in the clavus is supported by an interspinous bone, with the excep- 
tion of the middle four; these are associated with the last of the remaining vertebrae, 



THE OCEAN SUNFISHES {FAMILY MOLIDAE) loi 

which has no neural or haemal elements. There is no apparent reason why, if they 
also are dorsal and anal rays, they should not have their supports ; but if they are 
caudal rays they cannot be expected to be borne on hypurals, since these and other 
posterior vertebral elements have been lost. The presence of only four of these un- 
supported rays and the equal length of the dorsal and anal fin bases shows that 
Putnam's fish w^as a Masturus oxyuropiems ; two other dissections of this form have 
been illustrated — ^that by Gudger (1937 a, p. 41, fig. 27), and that by Raven (1939 6), 
The first does not show the internal skeleton, and one of the caudal rays is doubled, 
as can be seen by the nature of its basal cartilage ; but Raven's illustration, drawn by 
Helen Ziska, is admirable, and agrees in all essentials with that by Putnam. The only 
illustration showing the anatomy of M. lanceolatus is that given by Gudger in the 
work just quoted, based upon a young specimen (the same size as Putnam's) which 
was stained with alizarin and cleared. During the staining process some of the 
elements, notably the interneural supports of the clavus, were displaced, but I am 
satisfied that nothing was lost« This illustration is copied here as my Fig, 7 B, Here 
it will be seen that the central lobe of the clavus is supported by eight rays whose 
only skeletal support is the last vertebra (which has no neural or haemal elements) . 
Above these are five rays which can be associated with the five interneural bones 
which have been displaced from the horizontal during preparation. Below them are 
nine rays w^hich belong to nine interhaemals, the lower three of which have been dis- 
placed forward. The presence of eight rays in the caudal lobe of the clavus and the 
greater length of the base of the dorsal fin lobe as compared with that of the anal fin 
lobe shows this to have been a specimen of Masturus lanceolatus as identified by 
Klunzinger (a figure of whose specimen is given by Gudger), 

It is admittedly hazardous to speak of caudal rays when the hypural bones are lost, 
since in normal fishes caudal ra^^s are distinguishable only by their association with 
the hypnrals. But I feel convinced that these central rays of the clavus in Masturus 
are homologous with the hypocaudal rays of the more generalized forms, and it 
remains for me to suggest how it is possible for them to persist although their skeletal 

supports are lost. 

It has to be borne in mind that two opposing forces are involved during the de- 
velopment of the caudal region, interacting in different proportion at successive stages. 
First there is the reduction of the larval tail and the atrophy of the posterior vertebral 
elements, and secondly the normal growth of body and fins. 

The first process evidently begins at an early age, for Schmidt has figured a larval 
specimen in which, as Gudger has pointed out, dorsal and anal rays are present but 
not caudal rays ; development of the latter is retarded. To see how this fact may affect 
later stages it is necessary to consider what occurs in the Triacanthodidae, the most 
primitive family of Plectognathi, In the larval Triacanthodid (Fig. 8), the caudal 
rays are twelve in number, as in most Plectognathi, but the last four lie in relation 
to the end of the notochord, which will later become ossified as the urostyle ; the 
anterior eight belong to the last few myotomes. Degeneration of the tail from the 
rear will mean that the end of the notochord is lost first, and if this occurs before the 
hypocaudal rays appear not more than eight of them will develop. The eight slender 
rays of Masturti^s lanceolatus thus become intelligible and significant, while the 



I02 



THE OCEAN SUNFISHES {FAMILY MOLIDAE) 

presence of only four in M, oxyuropterns suggests that reduction has proceeded still 
farther before caudal rays begin to develop in this form. Comparison with the larval 
Mola figured by Sanzo (1939) is interesting in this connexion, for it will be seen that 
if in his specimen hypocaudal rays were developed, they would not be associated 
with myotomes, and this probably accounts for their absence in that genus. 

As the caudal rays become stronger the axial structures decrease rapidly, so that 
by the time the rays are brought to the homocercal position there are no hypurals for 
their support, nor neural or haemal elements for the last few vertebrae ; but normal 




* ' " * • * » ■ *■* 1-^ i-^— ■* ■ ; ^-r i * ** 

' * ■ * I * m * \ * • _^ » ■*■ ■ * */ 




Fig. 8. Caudal region of post-larval Triacanthodid fish, showing relationship 

of hypocaudal rays to notochord and myotomes. 



body growth has extended the posterior parts of the dorsal and anal fins with their 
supporting structures backward and downward to fill the void. This process is 
probably correctly demonstrated by Ryder's diagram, upon which mine is based 
(Fig. i) , in which the region of atrophy is delineated by the broken line. The vertebrae 
with their neural and haemal arches and spines are lost, but the interneural and 
interhaemal spines develop in relation to the fins in the normal manner except that 
they ultimately become tilted nearly at right angles to the last developed vertebral 
elements (Fig, 7), The number of these interspinous bones does not give a reliable 
estimate of the number of vertebrae that have been lost, because reference to the 
dissections show^s that more than one may be associated with each neural or haemal 
spine, while of course the last few vertebrae are probably not associated with inter- 
spinous bones at all. Ryder, of course, thought Putnam's young fish was a Mola 
and that the caudal rays were completely lost in the adult, A curious feature of the 
posterior migration of the dorsal and anal fins is that, while in the lobes the rays are 
more numerous than the interspinous bones, each of those in the clavus has its own 
supporting element ; this might be taken to indicate that the central rays, which I 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



103 



regard as caudal, are simply the last dorsal and anal rays, which are therefore more 
numerous than their supports in this region also, but there seems no good reason why 
the odd rays should all be crowded at the end. A more difficult argument to combat 
is that the supporting elements of these last rays cannot develop because of the 
presence of the vertebral column ; against this I can only point out that in Putnam's 
fish two elements lie behind the last vertebra, and there seems no reason why, if the 
odd four rays were in the same series, their supporting bones should not be there also. 
In fact, the presence of the two elements mentioned is reminiscent of the condition 



A 




B 



H 




INT 



Fig. 9, Masturus oxyuropterus, late post-larva (21 mm<), in British Museum collection, 

section of same specimen, showing presence of air-bladder, 
AB, air-bladder; h, heart; k, kidney; l, liver; int^ intestine; spLj spleen* 



B, dis- 



shown in Cyema atrum by Trewavas (1933); who identified the two small ossifications 
as hypurals. But since the last caudal vertebrae are so obviously lost in the MoUdae 
it would be incautious to speak of hypurals here, 

McCulloch has left us drawings of very young examples of both M, lanceolatus and 
M. oxyuropterus , at the stage when the larval tail is not quite lost, the sniall peduncle 
bearing its allotted quota of caudal rays and the dorsal and anal fins extending round 
to meet them. Knowing what a careful observer and excellent draughtsman McCul- 
loch was, I am prepared to accept these as good evidence. Eventually, at the better 
known stage of 50 mm. or thereabouts, there is no sign of the original tail, but the 
'caudal rays project beyond the rest of the clavus as the basis for the ultimate central 
lobe. Gudger believed that even these central rays were lost, at what he called the 
'square-tailed ' stage, but as this was based on the two obviously damaged specimens 
of Steenstrup & Liitken, this seems to be improbable — a point which Dr. Gudger 
himself has conceded in a letter to me. 

As a matter of interest I may mention here that in these small specimens it appears 
that the air-bladder is still present ; one which I dissected (Fig. 9 b) had a very 

ZOOL. I. 6 N 



I04 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



delicate, bubble-like structure at the centre of mass, which unfortunately collapsed 
while I was examining it. At this planktonic stage in its development such an organ 
is not surprising, and of course the Molidae are evolved from fishes in which the air- 
bladder is well developed, but it is worth noting that the statement that an air-vessel 
is absent in this family is probably true only of adults. 



L _ _ - ' 




Fig. 10, Masturus lanceolatus, adult. Singapore, (After Smedley, 1932.) 

With the development of the skeletal structures (poorly ossified though they are) 
atrophy proceeds no farther, and the processes of growth produce what later changes 
we can observe in the fish. An extension of the dermis and its collagenous sub- 
stratum, probably that which would develop over the caudal peduncle in a more 
normal fish, eventually covers the caudal lobe and the whole clavus. 

These are w^hat seem to be the main features in the development of the clavus of 
Masturus, but there is a certain amount of individual variation. In Af. lanceolatus 
the presence of eight caudal rays seems to be fairly consistent, but the middle ones 
are sometimes represented only distally — whether their proximal ends atrophy in the 
early stages or degenerate later is not evident. In M. oxyuropterus four caudal rays 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 105 

are usual, but may occasionally be five (as in a dissection figured by Gudger, wherein 
one of the rays had split or doubled as shown by its supporting cartilage) or rarely 
three. On pubUshed evidence the number of rays supporting dorsal iin, clavus, and 
anal fin respectively appear to differ very greatly, but most of these are of doubtful 
value, for an accurate count can only be made by dissection {except possibly in 
stuffed specimens). As an example of this may be quoted the description by Gudger, 
a careful worker, of the specimen he obtained for the American Museum of Natural 
History. In this he counted, on external examination, 'D.+C.-hA. complex = 60' ; 
the fish is in other respects M. oxyuroptems, so that this high count would cast doubt 
on its distinctness from M. lanceolatus. But later Raven dissected this same fish, 
and his illustration shows distinctly the total of fifty-five rays which is usual in 
M. oxyuroptems. Consequently it has not seemed expedient to give any definite 
statement of the number of rays to be found in dorsal and anal fins and clavus 
respectively, but only to indicate the total number, which seems to be characteristic 
for each species. 

Whether or not I am correct in calling them caudal rays, the presence of median 
rays unsupported by interspinous bones is characteristic of Masiurus. In the adults 
all the rays of the clavus are simple, without distal ossifications. There is always a 
median projection to the clavus, and the body is rather more elongate than that of 
Mola, especially in the early stages. Osseous tubercles, the remains of post-larval 
spines, seem never to be retained anywhere on the body of the adult. 

Two forms can be recognized, treated here as species, but I suspect that further 
study will show them to be the sexes of one. They have been taken in the same 
localities, and sometimes together. The sexual dimorphism found to be present in 
Mola mala (p. 117) lends support to this idea. But with no knowledge of the sex of 
any recorded individual I can but state their characteristics and apply available 
names to them pending further information. 

Since all the literature before 1939 has been fully quoted and discussed by Gudger, 
I have not thought it necessary to repeat it all below, particularly as a number of 
records cannot be assigned with certainty, but full and discriminating reference has 
been made to Gudger's papers. 

KEY TO THE SPECIES OF MASTURUS 

L Profile of lower jaw more convex, usually projecting beyond the upper. Upper 
profile of head evenly convex. Base of dorsal lobe conspicuously longer than that 
of anal fin. Dorsal and anal fins and clavus with a total of 60 to 62 rays. Caudal 
lobe of clavus^ longer than head in perfect specimens (often mutilated), sup- 
ported by eight (rarely 7 or 9) rays . . . . .1, lanceolatus 

II, Profile of lower jaw less convex, straight or concave, not projecting beyond the 
upper. Upper profile of head with distinct concavity above the eyes. Bases of 
dorsal and anal fin lobes about equal. Dorsal and anal fins and clavus with a total 
of 55 to 57 rays. Caudal lobe of clavus shorter than head, supported by 4 (rarely 
3 or 5) rays ,.•..,,, 2. oxyuroptems 

The uncertainty of authors as to where dorsal and anal fins end and clavus begins, 

^ Measured from ' hinge * of clavus to tip. 



io6 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



and the obvious inaccuracy (already mentioned) of fin-ray counts made upon 
external examination, militates against giving counts for individual fins, but it may 
be, as suggested by Gudger's cleared specimen, that in M. lanceolatus there are more 




Fig, ir, Masturus oxyuropterus, adult, Tahiti. (After Gudger, 1935-) 



rays in the dorsal lobe than in M\ oxyuropterus . In the latter, on the other hand, the 
number of claval rays supported on interhaemal bones seems to be greater (10 to 12) 
than in M, lanceolatus (g). 

Although usually these types seem to be recognizable at an early age, there are 
some doubtful cases among young specimens, as might be expected if they were the 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 107 

sexes of one species. For example, if M. lanceolatus should be the male, it might be 
more like the female [M, oxyuroptems) when young, as in many other fishes, and in 
fact small examples of the oxyuropterus type seem to be the more common. 

Masturus lanceolatus (Lienard) 

Orthagoriscus lanceolatus Lienard, 1840, Revue ZooL: 291; 1841, Magasin ZooL (2) 3 {Paiss.): 

pL 4. 
Orthagoriscus mola Klunzinger, 1871, Verh. ZooL-Boi. Ges, Wien, 21: 648; Giinther, 1880, Introd. 

Stud. Fish.: 175, fig. 94; Perugia, 1881, Ann. Mus. Star. Nat, Geneva 37: 365, fig. 
Mola mola CoUett, 1896, Risult. Camp. Set. Monaco 10: 163, pL 6, fig. i. 
Ranzania truncata Steenstrup & Liitken, 1898, K. danske vidensk. Selsk. Skr. (6) 9: pL 6, fig. C* 

(Not of Jordan & Gilbert, 1883.) 
Mola [Molacanthus) sp. McCuUoch, 1912, Proc. Linn. Soc. NSW, 37 (3): 553, pL 58. 
Mola lanceolata Schmidt, 192 1, Medd. Komm, Havunders0g, KbK, Fisk, 6 (6): pL i, figs, 4, 5; 

1932, Dana's Togtomkr. Jordr. 255, fig. 167 [part.); Barnard, 1927, Ann. S, Afr. Mus. 21: 

987, fig, 31 ; Ehrenbaum, 1936, Handb, Seefisch, Nordeurop. 2; 88; J. L. B. Smith, Sea Fish, 

5. Afr.\ 422, fig. 1214, 
Masturus lanceolatus Hubbs & Giovannoli, 1931, Copeia, 1931: 135 ; Gudger, 1935, Amer. Mus. 

Novit. 778: i, fig* i ; Gudger & McDonald, 1935, Sci. Man. 41: i, figs, 4-9, 11, 14, 15; Rivero, 

1936, Amer. Nat. 70: 92, fig.; Palmer, 1936, Science, 83: 597; Gudger, 1937^ Ann. Mag. Nat. 

Hist. (10) 19: 9i fig* 6; 15, fig. 10; 31, fig, 19; 33, fig. 20; 34, fig. 21 ; 38, fig. 23 ; Proc. ZooL Soc. 

Lend. 107 (A) (3) : 353 {part.), text-figs, i, 2, 4, 6, 7, 8, 9, 14 ( ?), 16, 20, 21 (?) ; pi. i, figs, 3, 4 ; 

pL 2, figs, 5, 6; pi. 4, fig, 10; 1939, /. Elisha Mitchell Set. Soc. 55 (2) : 305 ; Brimley, 1939, ibid, 

295, pL 28; Fitch, 1950, Calif. Fish Game, 36 (2) : 65. 

Lienard 's figure cannot be said to be notable for its faithful representation, but as 
it shows the caudal lobe indubitably much longer than the head and the base of the 
dorsal fin longer than that of the anal, it shows to which of our two forms the name is 
applicable. The fin-rays are always more easily seen in dried specimens of these 
fishes, and so Klunzinger's stuffed example shows the structure of the clavus very 
well ; it is closely similar (in this 65-in. example) to that of Gudger 's 53-mm. cleared 
specimen. Other figures in Gudger 's papers which appear to represent this form are 
stated in the above synonymy. Where the caudal lobe is mutilated or otherwise 
doubtful the broad dorsal base and rather pugnacious-looking 'chin' are the most 
useful distinguishing characters. 

It grows to a great size, the largest recorded specimen being lo ft* long and 11 ft. 
3 in. from the tip of dorsal to tip of anal fins* In our collection it is represented 
only by the post-larval specimen figured by Giinther, 

Recognizable records of adults are from the Atlantic, o0 Florida, Havana, North 
Carolina, and Table Bay, South Africa, from the Red Sea, and from the Pacific at 
Tahiti. Young specimens have been taken off Alabama, Teneriffe, and in the South 
Seas. As this paper goes to press Fitch (1950) states that 100 post-larvae J to 2 in, 
in length have been taken from the stomachs of tuna in Hawaiian waters. 

Masturus oxyuropterus (Bleeker) 

Orthagoriscus spinosus Gatchet, 1832, Act. Soc. Linn. Bordeaux 5: 253. {Not of Cuvier, 181 7,) 
Orthagoriscus oxyuropterus Bleeker, 1873, VersL Akad. Amst. (2) 7: 151, fig. 



lo8 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



Mala rotunda Ryder, 1886, Rep. US, Fish, Comm. (1884): 1027, pL 8, fig. 5, (Not of Cuvier, 

1798.) 
Ranzania truncata Steenstrup & Liitken, 1898, K, danske vidensk. Selsk, Skr. (6) 9 (i): 98, pL 6, 

figs. D, E, (Not of Jordan & Gilbert, 1883.) 
Mola (Molacantkus) sp. McCuUoch, 1912, Proc. Linn. Soc. NS.W. 38 (3): 553 {part), pL 59. 



9 



FLORIDA 

FLORIDA 



ATLANTIC . 

FLORIDA T 

N, CAROLINA^ 
TA&LE BAY- - 
FLORIPA 




RED SEA__ 
HAVANA 



8^- 



7: 




TAHJTI .._ 



4 



_ 



\ 



FLORIDA 



r^M ^ - 



1 



MIAM», FLA 





HAX^AI* 
SlNQAPOKf 

FLORrDA 




FLORIDA 

Amboina 




^ N CAROLINA 



FEET 



Fig. 12. Diagram showing comparative ranges of size for the two species 

of Mastufus, based on recognizable records of adult specimens. 



Mola mola Townsend 1918, Bull. N,Y, ZooL Soc. 21: fig- (not of Linnaeus) ; Collett, i8g6. Result 
Camp. Sci. Monaco, 10: 163 {part) pi. 6, fig. i. ps 

Mola lanceolata Schmidt, 1921, Medd. Komm, Havunders0g. Kbh. Fish, 6 (6) {part): pL i, fig. 
6; Smedley, 1932, Bult Raffles Mus. 7: 17, pL 

Masturus lanceolatus Jordan & Jordan, 1925, Mem. Carneg. Mus. 10; 89, fig. 7; Gudger & 
McDonald, 1935, 5^^- ^<^^' 41: i, figs. 3, 10, 12, 13 ; Gudger, 1935, Copeia, 1935: 35* figS- 1,2; 
1937, ^^w- Mag. Nat Hist, (10) 19: i {part), text-figs, iS, 22, 26, 27; 1937, Proc. ZooL Soc, 
Land, 107 (A) (3}: 353 (part), text-figs. 5, lo, 12, 13, 15, 18 (?), 19, 22, pi. i, figs, i, 2, pL 3, 
fig* 9 { ?)j pl' 4, fig- II, pi- 5, fig. 17; i939t /. Elisha Mitchell Sci. Soc. 15 (2) : 305 (part,), figs* 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 109 

1-5 ; Brimley, 1939, ibid, 300, pi. 29 ; Raven, 1939, Bull, Amer. Mus. Nat. Hist. 76 (4) : 143, pi. 
2; Hardenberg, 1939, Treubia 17 (2): 121 ; Clark, 1949, Amer. Mus. Novit. 1397: 7, fig* g. 

A high proportion of the young specimens recorded seem to belong to this form, 
but a possible explanation of this is given on page 107. The small number of support- 
ing rays in the caudal lobe, the equal bases of dorsal and anal fins, and the compara- 
tively weak-looking 'chin' are recognizable even in McCuUoch's lO-mm. specimen. 
The concavity of the dorsal profile of the head, however, is not noticeable in very 
small specimens, but it is already apparent in the 152-mm. example figured by 
Gudger (1939). The latter paper is also interesting in that it shows branching at the 
tips of the rays of the clavus, like that illustrated by Ryder (Fig, 7 a in this paper), 
but very much smaller, evidently in process of reduction. Only these two records of 
such branching exist, probably because the tips of the rays have been damaged in 
most small specimens, and the branching is lost with age. 

This form is so often taken in the same locality as the preceding that it is almost 
certainly a sex of that species ; in some instances young specimens of both forms have 
been taken from a single predatory fish (e.g. McCulloch (1912), whose 13-mm. specimen 
is M Janceolahis and his lo-mm, specimen M. oxyuropterus ; or Gudger (1939), whose 
125-mm. fish is M\ oxyuropterus, whereas at least the 127'mm, fish, and possibly the 
130-mm. specimen also appears to be M. lanceolatus) . 

It will be noticed that in each case the M. oxyuropterus is slightly the smaller, and 
the records of this form do tend to lie about a lower range of size (Fig, 12). The 
largest record seems to be the 'Miami Masturus no. Ill' of Gudger, figured by 
Gudger & McDonald, though the identification of this badly slung specimen is a little 
doubtful. It was 7 ft. in length. 

Recognizable records of adults of this form are from the Atlantic at North Carolina 
and Florida, from Singapore and Amboina, and from the Pacific at Hawaii, Young 
specimens have been taken at Florida, the Sargasso Sea, the Azores, and in the South 
Pacific. 

A young specimen (Fig. 9) of unknown provenance is in our collection, and a plaster 
cast of the specimen dissected by Raven is exhibited in the fish gallery of the British 
Museum (Natural History). 

Genus MOLA Koelreuter 

Mola Koelreuter, 1770, Novi Cofnment. Acad. PetropoL 8: 337. Type: Mala aculeata Koelreuter 

(— Tetraodon mola Linnaeus, young). 
Orihragoriscus Bloch & Schneider, 1801, Syst. Ichth.: 510. Type: Tetraodon mola Linnaeus. 
Cephalus Shaw, 1804, Gen. ZooL 5: 437- Type: Tetraodon mola Linnaeus. 
Ofthragus Rafinesque, 18 10, Caratt. Sicilia: 17. Type: Orthragus luna Rafinesque {= Tetraodon 

mola Linnaeus), 
Diplanchias Rafinesque, 1810, ibid. Type: Diplanchias nasus Rafinesque, 
Orthagoriscus Cuvier, 1817, Regne Anim,, ed. i, 2: 149. Type: Tetraodon mola Linnaeus. 
Pedalion Swainson, 1839, Nat. Hist, Fish. 1; igg. Type; Pedalion gigas (Guilding) Swainson. 
Molacanthus Swainson, 1839, ibid. 2: 329. Type: Molacanthus pallasi Swainson (= Tetraodon 

mola Linnaeus). 
Ozodura Ranzani, 1839, Novi Comment, acad. Set, Inst, Bonon, 3: 80. Type: Ozodura orsini 

Ranzani, 
Tympanomium Ranzani, 1839, ibid,, table. Type: Tympanomium planci Ranzani. 



no ^ THE OCEAN SUNFISHES (FAMILY MOLIDAE) 

Trematopsis Ranzani, 1839, ibid., table. Type: Trematopsis wiUoughbii Ranzani. 

Pallasina Nardo, 1840, Ann. Sci. Regno Lombardo-V eneto 10: 10, 112. Type: Pallasina pallasi 

Nardo (larval form). 
Acanthosoma De Kay, 1842, Nat, Hist New York [ZooL) 3: 330. Type: Acanihosoma carinatum 

De Kay (= Tetraodon mala Linnaeus, young). 
Aledon Castelnau, 1861, Mem, Poiss, Afr. austr,: 75. Type: Aledon storeri Castelnan. 

Closely related to Masturus, but differing in that the clavus is supported entirely 
by elements from the dorsal and anal fins. The form of the body is relatively shorter^ 
conspicuously so in the young, and the post-larval spines are not entirely lost, the 
base of one at the chin or one on the snout, or both, remaining as a low bony boss in 
the largest examples. 

Very few post-larval specimens of Mola have been found, but the smallest, 5 mm. 
long, shows that there is an ' Ostracion boops' stage, and several examples of the 
secondary post4arval or 'Molacanthus' stage have been described; it is not known 
whether the 'cornicles' are ever as long as those of Mastums. 

Although a number of naturalists have believed in the existence of several species 
of Mola, and Ranzani went so far as to recognize five genera and eleven species, it has 
generally been believed, especially during this century, that only one widely dis- 
tributed species is admissible. 

My studies, however, show that while Mola mola is indeed wide-ranging, it is 
largely or entirely replaced in the South Pacific by a second species, distinguishable 
as follows: 

KEY TO THE SPECIES OF MOLA 

L Cla\nis supported by about 16 rays, 12 of which bear ossicles; the ossicles much 
broader than the spaces between them, and forming the margin of the clavus ; 
those borne on paraxial rays separate, much smaller than the others. No band 
of reduced denticles between dorsal and anal fins . . , i. ramsayi 

IL Clavus supported by about 12 rays, 8 or 9 of which bear ossicles; the ossicles 
widely separated, invested with cuticle, which grows beyond them to form lobes 
in large examples ; those borne on paraxial rays united to form a single ossicle 
larger than all the others. A band of reduced denticles, smoother to the touch, at 
base of clavus from dorsal to anal fin . , . • . •2- mola. 

The term 'paraxial rays* refers to the pair of supporting rays of the clavus the 
proximal ends of which lie nearest to the end of the vertebral column. The smooth 
band between dorsal and anal fins in M. mola is usually visible, marked by a fold 
posteriorly, and often differently coloured from the rest of the fish ; in doubtful cases 
the tips of the fingers will discern that this area is less rough than the body in front 
of it and the clavus behind it. 

Mola ramsayi (Giglioli) 

Orthagorisctis tmncatus Hutton, 1872, Fish. New Zealand: 73. (Not of Fleming, 1828,) 
Orthagoriscus 'mola Castelnau, 1872, Proc. ZooL Acclim. Soo. VicL 1; 211; 1875, Res. Fish, 

Austral: 3; Hutton, 1873, Trans. Proc. N,Z. InsL 5: 271; Macleay, 1875, Proc. Linn. Soc. 

NS.W. 1: 12; Johnston, 1883, Pap, Roy. Soc. Tasm.: 137; 1891, ibid.: 38; Hamilton, 1886, 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



III 



Trans. Proc, N.Z. In$L 18; 135: Williams, 1893, ibid. 26: no, pL 8a; Drew, 1897, ibid. 
29: 286; Parker, 1897, ibid,: 627; ? Fletcher, 1929, Proc. Linn. Soc. N,S.W, 54; 225, 227. {Not 
of Cuvier, 181 7-) 




Fig. 13. Mala ramsayi, adult, 2130 mm. long. New South Wales* (Drawn from 

the type of the species in the British Museum collection.) 



Orthragoriscus ramsayi GiglioU, 1883, Nature, Land. 28: 315 ; Ramsay, 1883, Cat, NSW. Court, 

Intern. Fish. Exhib.: 43. 
? Ortkagoriscus eurypterus Philippi, 1893, Chilen. Fische: 15, pL 6, fig, i (not seen). 
Mala mola Waite, 1907, Rec. Canterbury {N,Z.^ Mus. 1: 34; 1913, Trans. N.Z. Inst. 45: 223, 

pL g; 1921, Rec, S, Aust. Mus, 2: 198, fig. 332 ; 1923, Fish. S. Austral,: 230, fig, ; Phillips, 1919^ 

ZOOL, I, 6 o 



H2 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



Rep, Dom. Mus. N.Z.: 6; 1926, JV,Z, /, Set. Tech, 8 {3): 169, figs, 1-3; McCuUoch, 1922, 
Aust. ZooL 2 (3): 130, fig. 374 a] 1930, Mem, Anst. Mus, 5 {3): 436 {part,) ; Schneider, 1930, 




Fig. 14, Mola ramsayi, yoong adult, 410 mm, long, South Australia ( ?). (From 

specimen in spirits in the British Museum collection.) 

po, paraxial ossicles* 

Rev. ChiL Hist. Nat. 34: 200, figs. 36, 37 ; Fowler, 1945, ibid. 45-47: 170, fig. ; Morrow & Mauro 
1950* Copeia, 1950: 108, fig. 4 c. 
Mola ramsayi Whitley^ 193I1 ^^0. Aust, Mus. 18 (3) : 126 {part.), pL 16, figs, 3, 4, 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 113 

All the New Zealand records, most of the Australian, and the few Chilean specimens 
appear to belong to this species, though in many cases it is not possible to be certain. 
It may be assumed, therefore, that in the South Pacific it replaces the wide-ranging 
Af , mola. The two meet, however, in the Australian area, for Stead, McCuUoch, and 
Whitley have all figured specimens which were undoubtedly M. mola, Whitley 
including his specimen with one of the true M, ramsayi in the same paper under the 
latter name. 

The type of Orthragoriscus ramsayi Giglioli is in the British Museum (Nat. Hist.), 
Its locality w^as given as 'Southern Hemisphere', but a label accompanying the 
specimen states 'New South Wales', and it is known to have been taken on that 
coast {fide Whitley, 1931} , It was exhibited at the International Fisheries Exhibition 
in London in 1883 and later presented to the Museum by the Commissioners of the 
Exhibition. It is a very large stuffed skin, now in a rather dilapidated condition. 
The total length is 213 cm. (6 ft. 8 in.). 

We have, fortunately, a second specimen, in spirits^much smaller, of course ; it 
is without a definite locality, but almost certainly from South Australia, since it was 
in a collection of specimens presented by the Zoological Society, several of which 
were typical South Australian species and all of which would be likely to occur there. 
It agrees very weU with the excellent figure given by Waite {1923), and removes any 
doubt as to the distinctness of the species from M. mola. 

The type is not by any means the largest recorded specimen of M. ramsayi. That 
distinction apparently goes to one taken on 12 December 1889 in Poverty Bay, and 
recorded by Williams as measuring 9 ft. 8 in. and weighing 3^ tons. 



Mola mola (Linnaeus) 

Tetraodon mola Linnaeus, 1758, Sysi. Nat. ed. 10, 1: 334; Pennant, 1776, Brit. ZooL 3: 131, 
pi.; Migliorini Spinola, 1843, Poiss, Genes: 14* 

Teirodon mola Briinnich, 1768, Ichth, massiL: 8; Gmelin, 1778, Syst. Nat. Linn,: 1447; Retzius, 
1785, K, Svensk. Vetensk. Akad. HandL 6: 115; Bonnaterre, 1788, TahL EncycL Meth.: 25, 
pL 17, fig. 54; Lacepede, 1798, Hist. Nat, Poiss. 1; 509; Retzius, 1800, Fauna Suec: 310; 
Donovan, 1803, Nat. Hist. Brit- Fish. 2: pi xxv. 

Mola aculeata Koelreuter, 1770, Novi Comment. Acad. PetropoL 8: 337. 

Diodon mola Pallas, 1777, Naturgesch. Thiere 8: 41, pL 4, fig. 7; Bloch, 1785, Naturgesch. 
ausldnd, Fische 1; 75, pL 128; Jacob. 1826, Dublin PhiL J. 2: 443, pL 

Mola rotunda Cuvier, 1798, TabL Elem. Nat, Hist, : 323 ; Jordan, 1881, Proc. US. Nat, Mus.: 70; 
Jordan & Gilbert, 1883, Bull, US. Nat, Mus. 16: S65 ; Petersen, 1884, Vidensk. Medd, naturh 
Foren, Kbh,: 159; Smith, 1885, W, Amer, Sci. 1 (7): 45; Linton, 1897, Proc. U,S, Nat, Mus 
19: 788, 812, 824; Steenstrup & Liitken, 1898, K. Danske vidensk. Selsk. Skr. (6) 9 (i): 28 
pi. I ; Murray & Hjort, 1912, Depths of the Ocean: 119, 607, 615, 697, figs. 102, 507; Schmidt 
1921, Medd, Komm, Havunders0g, Kbh. Fisk, 6: i, figs, i, 5, 6, 10 6, 12, pL r, figs, i, 2 ; 1926 
Nature, Land, 117: 80, figs, r, 2; Ehrenbaum, 1936, Handb, Seefisch. Nordeurop, 2: 86, fig, 68 
Jensen, 1940, Vidensk, Medd, nat, Foren, Kbh, 104: 319. 

Orthragoriscus mola Bloch & Schneider, 1801, Syst, Ichth.: 510; Turner, 1862, Nat, Hist, Rev, 
185, pi, 6, figs, 4-6; Beneden, 1871, Mim. Acad, R, Belg. 38; Jeude, 1890, Notes Leyden Mus, 
12: 189, pL; Roon & Pelkwijk, 1939, Zool. Meded, Leiden 22: 65, figs, i, 2. 

Orthragoriscus fasciatus Bloch & Schneider, 1801, Syst, Ichthr, 511. 

ZOOL. I. 6 02 



114 THE OCEAN SUNFISHES (FAMILY MOLIDAE) 

Orihragoriscus hispidus Bloch & Schneider, 1801, ibid.: 511. 

Cephalus brevis Shaw, 1804, Gen. ZooL 5: 4371 pL 175; Neill, iSir, Mem. Werner. Soc. 1: 546; 
Mitchiil, 1815, Trans, lit. phiL Soc. N,Y. 1: 471; Swainson, 1839, NaL Hist. Fish. 1: 199. 

Cephalus pallasianus Shaw, 1804, Gen. ZooL 5: 440, 

Ortkragus luna Rafincsque, 18 10, Caratt. Sioiliai 17-18; Indies Siciliana: 40, 

Diplanchias mala Rafinesque, 18 10, ibid, 

Cephalus mala Risso, 1810, Ichth. Nice: 60; Poey^ 1868, Repert. Cuba 2: 433. 

Ortkagorisctis mala Cuvier, i8ij, Regne Anim., ed. i, 2: 149; Fleming, 1828, Hist. Brit. Anim.: 
175; Nilsson, 1832, Prodr. Ichth, Scandinav.: iii; Jenyns, 1835, Man. Brit, Vertebr, Anim.\ 
490; Storer, 1839, Fish. Massachusetts: 170, pL 3, fig. i ; Swainson, 1839, Nat, Hist, Fish. 2: 
329, fig< 107; Bellingham, 1840, Mag, Nat. Hist, (n,s.), 4: 235; Bennett, 1840, Narr. Whaling 
Voy. 2: 262 ; Wellenbergh, 1840, Dissert. Inaug,, Lugd. Batav., pi, ; Goodsir, 1841, New Philos, 
/. aO: 188, pi 4; De Kay, 1842, Nat. Hist. N.Y. {ZooL), 3: 331, pi 59, %. i93 ; Storer, 1846, 
Mem, Amer. Acad, Arts Sci, N.s. 2: 495; Dilwyn, 1848, Mater, Fauna Swansea: 15; Parlby, 
1848, Proc, ZooL Sac. Lond. 17: 6; 1850, Ann, Mag. Nat. Hist. (2) 5: 53 ; Schlegel, 1850, Fauna 
Japonica {Poiss.): 288, pi 127; Costa, 1850, Fauna Regn. Napoli {Pesci, Pleitognathi) \ 28, 
pis* 63^4; Smith, 1851, Ann. Mag. Nat. Hist, (2) 8: 347; Kroyer, 1852, Danmarks Fisk. 
3: 732 ; Embleton, 1854, Trans. Tyneside Nat. 2; no, pi 3 ; Nilsson, 1855, Skandinav. Fauna: 
697; Thompson, 1856, NaL Hist. Ireland ^i 243 ; Kolliken i860, Verh. phys-med. Ges, Wurzburg 
10: xxxviii; Cleland, 1862, Nat. Hist, Rev.: 170, pL 5-6; Storer, 1863, Mem, Amer, Acad. 
Arts Sci. N.s. 8 (2) : 420, pL 34, fig. 2; Beltremeux, 1864, Ann. Acad, la Rochelle [Faune] : 53; 
Couch, 1865, Hist. Fish. Brit. Is. 4: 377, pi. 245; Blanchere, 1868, Nouv. Diet, peches: 505, 
fig. 673; Schlegel, 1869, Nat. Hist. Ned. Vischen: 182, pi 17, fig. 4; Gunther, 1S70, Cat, Fish. 
Brit. Mus. 8: 317; Capello, 1870, /. Sci, Math. Phys. Nat. Lisboa2: 136 ; 1881, Mem, R. Acad. 
Lishoa: 41; Andrews, 1871, Proc. NaL Hist. Sac, Dublin (1865-1869), 5 (i): 123; Putnam, 
1871, Proc. Amer. Ass. Adv. Set. 19: 255; Amer. Nat. 4: 629, figs, 134, 137; Jourdain, 1871, 
C. R. Acad. Sci. Paris 63: 1225; Canestrini, 1872, Fauna d' Italia {Pesci): 148; Barker, 1876, 
Zoologist: 5087; Malm, 1877, Goteborgs Fauna: 599, 654; Winther, 1879, Nat. Tidsskr. (3) 
12: 54; Stossich, 1879, Boll. Soe. Adriat. Sci. NaL 5: 36; Moreau, 1881, Poiss. France 2: 74; 
Vignal, 1881, Arch. ZooL exp. gen. 9: 369, pi 21 ; Campbell, 1883, Proc. Nat. HisL Soc. Glasgow 
(1882) 5: 176; Day, 1884, Fish. GL Brit. 2: 272, pi 148; Thompson, 1888, Anat. Anz. 3: 93, 
figs, ; i88g. Stud. Mus, ZooL Univ. Coll. Dundee 1, No. 4; Vinciguerra, 1890, Boll. Mus. ZooL 
Rome 1: 33; Haller, 1891, Morph. Jb. 17: 198, figs,, pis, 13-X5; Steindachner, 1891, Ann. 
Naturh, Hofmus. Wien 6: 90; Almeida & Roquette, 1892, Inquir, Industr., Lisboa 2: 377; 
Girard, 1894, -^^^^ Set. NaL, Porto 1:31; Tagliani, 1894, Monit. ZooL itaL 5: 248 ; Grieg, 1895, 
Bergens Mus, Aarb. 6; n; Smitt, 1895, Skandinav. Fisk, 2: 622, figs. 153, 154 a, 156, 157, 
pL 27, fig. 4 ; Osorio, 1896, /. Sci, Math, Phys, Nat. Lisboa 4: 157 ; Vieira, 1898, Ann. Sci. Nat., 
Porto: 24; Clarke, 1898, Zoologist 16: 439; Andersson, 1900, Ofvers. Vetensk Akad. Forh., 
Stockh.: 603; Parker, igoo, AnaL Anz, 17: 313, fig.; Herdman & Dawson, 1902, Mem, Lanes, 
Sea Fish. Comm. 2: 57 ; Griffini, 1903, IttioL ItaL: 155, figs, 81, 82 ; Michailovskij , 1903, Annu. 
Mus, ZooL, Acad. St. Pdtersb. 8:xlvi; Meek, 1904, Anat. Anz. 25: 217, fig. ; Dall, 1908, Bull. 
Mus. Camp. ZooL Harv. 43 (6) : 232 ; Novikov, 1909, Dnevn. russkh. Estesiroisp. 1909- 
1910; 286; 1910, Anai. Anz. 37: 97; Sauvage, 1910, M^m. Soc. Hist, Nat. Auiun, 23: i; 
Giinther, 1910, /. Mus. Godeffroy 9(17); 477; Seabra, 191 1, BulL Soe. Portug. Sci. Nat.: 193; 
Le Danois, 1913, Poiss. Manche occ. : 106, fig, 182 ; Kaschkarov, 1916, Rev. ZooL Russe 1: no, 
figs, 1-12 ; Thompson, 1918, Scot. Nat. : 41, 59 ; Kincaid, 1919, Annoi. List. Puget Sound Fish. : 
23, fig. 43 ; Toni, 192 1, Atti IsL Veneio 80: 125 ; Grenholm, 1923, Stud. Floss. Teleost. Upsala: 
240 ; Patroni, 1923, ^Hf*, Mus. zooL Napoli, n.s, 5 (4), pi i ; Jenkins, 1925, Fish. Brit. Is,: 212, 
pi 85 ; Duncker & Mohr, 1926, in Grimpe & Wagler, Tierwelt Nord u. Ostsee 4 (12) : Xllg 29, 
figs. 4, 5; Gudger, 1928, Sci, Mon. N.Y.: 257; Burr, 1928, /. Comp. Neurol. 4S: 33, figs.; 
Caraffa, 1929, Poiss. Corse: 50, fig.; Marine Biol Ass, 1931, Plymouth Mar. Fauna: 318; 
Saemundsson, 1931, Nat. Reykjavik 1; 164; 19391 Vidensk. Medd. naturh. Foren. Kbk. 102: 
207; Noronha & Sarmento, 1934, P^i^^s Madeira: 121; Nobre, 1935, Fauna Mar. PortugaL 
Vertebr.: 240, fig, 109; Toschi, 1936, Boll. Pesca Piscicolt. IdrobioL 12: 325 ; Sanzo, 1939, Arch. 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 115 

zooL Torino 26: 121, pL 7, figs, 16, 17; Andersson, 1942, Fisk, Nord. 1: 62^ pL; Roon, 1942, 
ZooL Meded. 23: 313, fig- 

Orthagoriscus spinosus Cuvier, 1817, Rigne Anim. ed. 2, 2: 370; Richardson, 1844, Voy, Sulphur, 
Fish.: 125, pi. 62, figs, ro-12. 

Cephalus ortagoriscus Risso, 1826, Hist, etir, MSrid. 3: 173* 

Diodon carinatus Mitchill, 1828, Ann. Lyceum New York 2: 264, pL 5, fig. i. 

? Mola aspera Nardo, 182S, BulL Sci. Nat [Firussac] 8: 437; Bonaparte, 1846, Cat. met, pesci 
eur, : 87. 

Mala hispida Nardo, 1828, ibid,: 438, 

Pedalion gigas (Guilding) Swainson, 1839, Nat. Hist. Class. Fish, 1; 199, fig, 33. 

Molacanthus pallasi Swainson, 1839, ibid. 2: 329. 

Ozodura orsini Ranzani, 1839, Novi Comment. Acad. Sci, Inst, Bonon Zl 80, pL 6. 

Tympanomium planci Ranzani, 1839, ibid,, table. 

Diplanchias nasus Ranzani, 1839, ibid, 

Tremaiopsis willughbii Ranzani, 1839, ibid, 

Orthragoriscus reizii Ranzani, 1839, ibid.; Bonaparte, 1846, Cat. met. pesci eur.: 87. 

OrthragorisGus ghini Ranzani, 1839, ibid. 

Orthragoriscus rondeletii Ranzani, 1839, ibid. 

Orthragoriscus blochii Ranzani, 1839, ibid, 

Orthragoriscus alexandrini Ranzani, 1839, ibid,, pL 6; Alessandrini, 1839, ibid.: 359, pis. 31-34. 

Orthragoriscus redi Ranzani, 1839, ibid,, table, 

Orthragoriscus aculeatus Ranzani, 1839, ibid, 

PaUasina pallasi Nardo, 1840, Ann. Sci. Regno Lombardo-Veneto 10: 112. 

Acanthosoma carinatum De Kay, 1842, Nat. Hist. New York, ZooL 3; 330, pL 15, fig. 179; Storer, 
1846, Mem, Amer. Acad. Arts Sci. 2: 494* 

Molacanthus hispidus Bonaparte, 1846, Cat. met. pesci eur.: 87* 

Mola tuna Sassi, 1846, Saggio sopr, Pesci^ &c. : 35; Aradas, 1871, Ann. Min. Agric. Ind, Comm. 
1, pt, i: 587. 

Orthagoriscus analis Ayres, 1859, Pvoc, Calif. Acad. Sci. 2; 31, fig. 14; i860, ibid.: 54, fig, 5; 
Stearns 1867, ibid, 3: 341. 

Molacanthus carinatus Gill, i85i, Proc. Acad. Nat. Sci. Philad. (i860): 21. 

Aledon storeri Castelnau, 1861, MSm. poiss, ^f^* australe: 75, 

Aledon capensis Castelnau, 1861, ibid.: 76. 

Ma/£i ^asws Steenstrup & Liitken, 1863, Oz;er5. danske Vidensk, Selsk. Fork.: 36; Wahlgren, 
1868, Acta Univ. Lund. 4: i, pL 

Mola retzii Steenstrup & Ltitken, 1863, ibid. ; Wahlgren, 1868^ ibid, 

Orthagoriscus sp. Swinhoe, 1863, Ann. Mag. Nat. Hist. {3) 12: 225. 

Orthagoriscus ozodura Harting, 1868, Verh. A had. Wet, Amst, 11: i, pis* 1-8. 

Orthagoriscus planci Stossich, 1879, BolL Soc. Adriat, Sci. Nat. 5: 36, 

Orthagoriscus nasus Jeude, 1892, Notes Leyden Mus. 14: 127, pi, 5; Tijdschr, Ned. Dierk. Ver, 
18: 185, pi. II. 

Orthagoriscus sp. Reuvens, 1894, Notes Leyden Mus. 16: 128, pi, 5. 

Mola mola Jordan, 1885, Proc. U.S. Nat. Mus. 8: 393; Eigenmann, 1893, ibid, 15 (1892): 131, 
175 ; Jordan, 1895, Proc. Calif. Acad. Sci, (2) 5: 491 ; CoUett, 1896, Result, Camp, Sci, Monaco, 
10: 163 {part.); Jordan & Evermann, 1898, Bull. U.S. Nat. Mus., No. 47, 2: 1753; H, M< 
Smith, i8g8. Bull. U.S. Fish. Comm. 17: 85; Linton, i8g8, Proc. U.S. Nat. Mus. 20: 507 et 
seq* ; Evermann & Kendall, 1899, R^p- U.S. Fish. Comm.: 88; Jordan & Snyder, igoi, Proc, 
U.S. Nat. Mus. 24: 260; Green, igoi, Bull. U.S. Fish. Comm. 19: 321 ; Jordan & Evermann, 
I902j Amer, Food and Game Fishr. 492, fig.; Gilbert & Starks, 1904, Mem. Calif. Acad. Sci. 
4: 206; Hargitt, 1905, BulL U.S. Bur. Fish, 24 (1904): 25; Stead, 1906, Fish. Austral.: 227, 
fig, 82; Starks & Morris, 1907, Univ. Calif. PubL ZooL 3 (n): 205; Murray & Hjort, 1912, 
Depths of the Ocean: 644; Halkett, 19131 Checklist Fish. Canada: 116; Dean, 1913, Amer. Mus, 
J. 13 {8): 370, fig, ; Hilton, 1914, /, Ent. ZooL 6 (4) : 233 ; Evermann, 1915, Copeia, 20: 17; 
Buen, 1919, BoL Pesc. Madr. 4: 295 ; 1935, Notas. Inst. esp. Oceanogr, 2 (89) ; 146; Dons, 1920, 



ii6 THE OCEAN SUNFISHES {FAMILY MOLIDAE) 

Tfoms. Mus, Adrsh. 43 (6): 38, pL 2; Jordan, 1921, Copeia, 93: 28; McCuUoch, 1922, 
Aust. Zooh 2; 130, pL 43, fig, 374^1; Fowler, 1923, Proc, Acad. Nat, Sci. Philad. 75: 294; 
WoUeboek, 1924, Norges Fiske: 224, fig, 254; Damant, 1925, Nature, Land, 116: 543, fig.; 
Bigelow & Welsh, 1925, Bull, U,S. Bur, Fish, 40 (i) : 301 ; Buen, 1926, Result. Camp, int. Inst, 
esp. Oceanogr. 2: 56; Barnard, 1927, Ann. S. Afr, Mus, 21: 986; Fowler, 1928, Mem. Bishop 
Mus, 10: 473; Ulrey & Greeley, 1928, BulL Calif. Acad. Sci, 27 (i) : 24; Breder, 1929, Field 
Book Mar. Fish. Atlanta Coast: 236, fig.; Hiibbs & Schultz, 1929, Calif. Fish Game, 15 (3): 
Ulrey, 1929, /, Pan-Pacif, Res. Inst. 4 (4) : 11, 235 ; McCuUoch, 1930, Mem, Aust. Mus, 5: 436; 
Myers & Wales, 1930, Copeia 1934: 11 ; Ancona, 1931, Fauna Flore Mediter., figs, i, 2 ; Breder, 
1932, Copeia (4) : 180 ; Gregory ^ ig^;i,Trans.Amer, Phil, Soc, 23 (2) : 294 ; Gregory & Raven, 1934, 
Copeia 4: 145; Barnard, 1935, Ann. S, Afr, Mus. 30: 645; Bamhart, 1936, Mar. Fish, South, 
Calif: 95, fig. 288 ; Tibby, 1936, Calif Fish Game 22 (i) : 49, fig* 22 ; Fowler, 1936, Bull. Amer. 
Mus. Nat. Hist, 170 {2) : 1123, fig, 469 ; Schultz & Da Lacy, 1936, Mid-Pac. Mag. 49 (3) : 211 ; 
Scofield, 1937, Calif, Fish Game 23 (4): 336; Schulte, 1938, Nat. Geogr. Mag. 74 (4): 497; 
Brimley, 1939, /* Elisha Mitchell Sci. Soc. 15 (2): 301, pi. 30; Deranyigala, 1944, /. Bombay 
Nat, Hist. Soc. 44 (3) - 429; Mendes, 1944, Bol. Fac. Files. Cien. Let. Univ. S. Paula, ZooL No, 
8: 173, pi. ; Engel, 1945, ZooL Meded. Leiden 25: ii, pi. i ; Clemens & Wilby, 1946, BulL Fish. 
Res. B. Canada 68: 330, fig,, 247; Medcof & Schiffman, 1947, Acadian Nat. New Brunswick 2; 
8, 63, fig,; Poll, 1947, Poiss. Mar.: 405, figs. 260, 261; Barnard, 1948, Ann. S. Afr. Mus, 
38 (5): 401, pis, 12, 13; Maul, 1949, Vettebr. Madeira, ed. 2, 2 (Peixes): 158; Clark, 1949, 
Amer. Mus, NoviL 1397: 7, fig, 9; J, L. B, Smith, 1949, Sea Fish. S. Africa: 422, pL 95, 
fig. 1213; Tortonese, 1950, Att. Ace. Ligure Sci. Q (i): 112, 

Orthragoriscus nasus Reuvens, 1897, Notes Ley den Mus. 18: 209, pi. 3. 

Mala ramsayi Whitley, 1931, Rec, Aust. Mus, 18 (3) : 126 {part,), fig. 2, pL 16, fig. i ; 1933, Vict. 
Nat. 49: 210, figs, i, 2 (not of Gigliofi). 

Mola alexandrini Barnard, 1948, Ann. S. Afr, Mus. 36 {5): 402. 

The above extensive synonymy illustrates the considerable literature which has 
accumulated concerning this species. From a perusal of this data it is possible to give 
a rather more complete account than for other members of the family, but there is 
still much of its biology that remains conjectural. The anatomy has been studied 
broadly and in detail by a number of workers, and from this, together with descrip- 
tions or figures giving reliable information about the clavus, it seems quite clear that 
not more than one species is involved. Published records, considered statistically, 
would give the impression that the species is mainly a North Atlantic one, becoming 
rarer southwards, in the Indian Ocean and in the Western Pacific, but this is possibly 
an illusion due to the much higher rate of publication in the Atlantic and Mediter- 
ranean countries. 

Certainly the Japanese form is not separable from the Atlantic form, since we have 
specimens from Japan in our collection for comparison; according to Jordan and 
Fowler it occurs at Hawaii, and it seems to be common at California, so that it is 
replaced by M. ramsayi only in the South Pacific. I am much indebted to Mr. W. I. 
FoUett, of the California Academy of Sciences, for information and radiographs which 
enable me to identify the Calif orni an specimens, 

A bad practice among some authors" is the borrowing of an illustration from some 
earlier work, especially when the specimen depicted was obtained in a locality remote 
from that being discussed. Mola mola has suffered much from this treatment, and 
in consequence it is not possible to be definite as to the identity of specimens in 
regions where M. ramsayi might occur also, because the distinguishing characters 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



117 



of the clavus have been hitherto unknown and are^ therefore^ not described; a re- 
hable picture might have given the answer. 

Comparison of adequate descriptions and figures shows that some order underlies 
the variability which has been remarked upon by so many authors. After meta- 
morphosis the young fishes are short and deep, the snout not protuberant, the fins 
rather narrow, and the margin of the clavus is not conspicuously lobed. The length 
of the clavus from the posterior edge of the 'carapace' — i,e. the anterior edge of the 
smooth band between dorsal and anal fins — ^is much less than that of the head. When 
the fish exceeds a length of about 2 ft., however, sexual differences become apparent • 
The bony tubercle on the snout is either pushed forward (in the male) , or upward (in 
the female) ; in consequence the male develops a 
pronounced snout, projecting forward (the 'nasus' 
form), while the female appears more deep-headed, 
with the front of the snout nearly vertical (the 
' alexandrint form). As growth proceeds the clavus 
develops backwards between the ossicles, forming a 
series of lobes w^hich at first number between g and 
12 in both sexes ; females do not seem to pass beyond 
this stage, but in large males the five median lobes 
become very large and the others reduced. After 
the formation of the lobes the clavus is probably 
alw^ays longer in a male than in a female of the same 
size, and in the biggest males it may be as long as the 
head. In large specimens of both sexes two prominent, 
swollen ridges are formed on each side of the head ; 
these are discernible in small examples, and are 
evidently analogous if not homologous with the late- 
ral ridges of Ostracionts, but with age they become 
very conspicuous. In the larger examples also the 
dorsal and anal fins are relatively much broader. 

All this is indicated by a study of the records. 
Comparatively few of the specimens described have 

been examined for sex, but in each case where the sex is stated the characters 
mentioned above are found to be associated with it ; of particular interest is the 
paper by Roon & Pelkwijk (1939), w^ho had both sexes and figured them together. 
Harting's (1868) plate i gives a fair representation of a female, and Whitley 
(1931) has given a drawing of another, together with a photograph of it (ph xvi, fig. i), 
which shows the lateral ridges excellently, and Murray & Hjort's (1912) photograph, 
copied by Schmidt, illustrates a fine male. The various phases of development out- 
lined do not alw^ays coincide with a particular size or age, but are evidently dependent 
to some extent on environmental circumstances. 

Mala mala growls to a great size, the largest record being apparently that by Dean 
(191 3), measuring 10 ft. i in. in length and 11 ft. from tip of dorsal fin to tip of anal 
fin, a male. Mikailovskij (1903) described one measuring 8 ft, 6 in, in length and 
weighing 1,410 kg. Jeude (1890) described a specimen 2-23 m, {7 ft.) in length, 




Fig. 15. Post4arvae of Mola, A, 
'Osf radon hoops' stage (5 mm.}. 
(After Schmidt) ; B. 'Molacanthus' 
stage (16 mm.). (From specimen 
in the British Museum collection.) 



ii8 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



apparently a female. The specimen recorded by Giinther as ' 7 feet long, Portsmouth ' 
was the fish taken by Parlby (1849), who described its capture at Chesil Beach and 




Fig. 16. Mola mala, adult, 600 mm. long, Plymouth, (From stuffed specimen 

in the British Museum collection,) 
NA, area of reduced denticles ; po, paraxial ossicle. 

stated that it measured 6 ft. 3 in. long. It was probably a male. As a stuffed skin it 
remained in the British Museum collection until recently, when it was found to be in 
a bad state and destroyed ; my (calliper) measurement at this time reading 5 ft, 8 in., 
the loss being presumably due to shrinkage (unless Parlby made a contour measure- 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) 



iig 



ment) , A number of smaller stuffed skins and several specimens in spirits remain in 
the collection. It is never common, the large Uterature being due to the great interest 




Fig, 17, Mola mala, young adult, 366 mm. long. Chouse, Japan. {From 

specimen in spirits in the British Museum collection.) 

it arouses, almost every specimen being reported upon ; but it is more frequently met 
with than any of the previous species. Nevertheless its early developmental stages 
are less well known than those of Ranzania, and fertile eggs or early larvae have not 
been found ; it is not improbable that it spends a great part of its life in deep water. 



I20 



THE OCEAN SUNFISHES {FAMILY MOLIDAE} 

The scarcity of young specimens is remarkable when we consider that a female 
4 ft, 6 in. long contained 300 million eggs. The mode and place of breeding have yet 
to be found. 

Its migrations inshore are unpredictable, and are usually supposed to coincide with 
invasions of medusae, salps, and ctenophores, upon which it largely feeds. Specimens 






Fig. 18, Different lobulation of the clavus, with similar skeletal 

supports, in Mola mola. Drawn to the same size for comparison. 

That on the right is the characteristic form in large males. 



taken inshore, however, are usually found to be feeding on littoral forms, and the list 
of organisms taken from stomachs includes Crustacea, ophiuroids, molluscs, hydroids, 
ctenophores, corallines, and algae ; Schmidt has reported them as feeding heavily on 
leptocephali ; on one occasion a flounder {Plaiichthys flesus) was found in the throat 
(Reuvens, 1897), and in our collection there is a Hng [Molva macwphthalma) two feet 
long which was taken from the stomach of Mola mola. The stomach is not infrequently 
found to be empty, and it is quite probable that the specimens so frequently taken 
without difficulty while 'basking' at the surface are in fact sick or dying fish. Myers 
& Wales (1930) found young fish to be active and alert, but later found two larger fish 
* disabled* at the surface. It would be interesting to know the cause of such disable- 
ment. Possibly the great variety of parasites with which they are often found to be 
infested may have some bearing on the matter. 



THE OCEAN SUNFISHES (FAMILY MOLIDAE) i3i 

REFERENCES 

Barnard, K, H, 1927, A Monograph of the Marine Fishes of South Africa. Part IE Ann. S. 

Afr, Mus. SI (2): 419-1065. (MoHdae, p. 984,) 
1935* Notes on South African Marine Fishes. Ann. S. Afr, Mus. 30 (5): 645-658, pis, 

23-25, (Mohdae, p. 635, figs. 5-7,) 
Chabanaud, P, 1935. Quelques Monstruosit^s chez des Poissons H^t^rosomes. Arch. Mus, 

Hist Nat. Lyon, 15: 1-23, 4 pis. 
Fraser-Brunner, a. 1943* Notes on the Plectognath Fishes. VI IE The Classification of the 

Suborder Tetraodontoidea, with a Synopsis of the Genera, Ann. Mag. Nat. HisL (11) 

10: 1-18, 

Gregory, W. K., & Raven, H. C. 1934* Notes on the Anatomy and Relationships of the Ocean 

Sunfish [Mola niola). Copeia, No. 4: 145-151, pi. 
Green, E, H, 1901, The Chemical Composition of the Sub-dermal Tissue of the Ocean Sunfish, 

BtilL US, Fish Comm, 19: 321, 
GuDGER, E. W, 1937 ^- The Structure and Development of the Pointed Tail of the Ocean 

Sunfish Masturus lanceolatus. Ann. Mag. Nat. Hist. (10) 19: 1-46, pis. 1-2, 
1937 ^* The Natural History and Geographical Distribution of the Pointed-tailed Sunfish 

{Masturus lanceolatus) with Notes on the Shape of the Tail. Proc. Zooh Soc. Lond. (A) pt, 3 : 

353-396, pis. 1-4. 
McCuLLOCH, A. R. igi2. A Description and Figures of Three Specimens of Molacanthus. Proc. 

Linn, Soc. N.S.W. 37: 553-555, 2 pis. 
Pellegrin, J, 191 2. Sur la presence d*un banc de Ranzania iruncata Retzius a la Martinique. 

Bull. Soc. Zooh France, 37: 228-230, fig, i. 
Raven, H. C. 1939 a. Notes on the Anatomy of Ranzania truncata, Amer, Mus, Novit. 1038: 

1939 6. On the Anatomy and Evolution of the Locomotor Apparatus of the Nipple-tailed 

Sunfish {Masturus lanceolatus). BulL Amer. Mus. Nat. Hist. 76 (4) : 143-150, pi. 2. 
Ryder, J. A. i886* On the Origin of Heterocercy and the Evolution of the Fins and Fin-rays 

of Fishes. Rep. U.S. Fish Comm. 1884: 981-1085, 11 pis. 
Sanzo, L. 1939. Rarissimi stadi larvali di Teleostei. V. Orthagoriscus mola Linn, Arch, zool. 

Torino 26: 143-146, pL 7, figs, 16-17, 
Schmidt, J, 1932. Dana's Togt omkring J or den. igzS-^o. 368 pp. (Molidae, p. 249 et seq,) 

Kobenhavn. 
Trewavas, E. 1933. On the Structure of Two Oceanic Fishes, Cyema atrum Giinther and 

Opisthoproctus soleatus Vaillant, Proc. ZooL Soc. Lond. (3) : 601-614, ^ P^^- 
Whitley, G. P. 1931- Studies in Ichthyology No. 4, Rec. Aust Mus. 18 {3) : 96-133, pis, 11-16. 

(Molidae, p. 126, fig. 2, pi, i6*) 




PRESENTED 

3 1 OCT 1951 



PRINTED IN 

GREAT BRITAIN 

AT THE 

UNIVERSITY PRESS 

OXFORD 

BY 

CHARLES BATEY 

PRINTER 

TO THE 
UNIVERSITY